afni.nimh.nih.gov

> aren't I losing the ability to look at a main effect of time?

The main effect of the time is still included in the output, which essentially tests the area under the HDR curve.

> Is there possibly another solution which would allow me to specify AR1 or another autoregressive structure?

It's difficult to do that with more than one group of subjects. I'd not worry too much about that.

Gang